$\begin{cases} f(1)=-2 \\\\ f(2)=5 \\\\ f(n)=f(n-2) \cdot f(n-1) \end{cases}$ $f(3)=$
Solution: ${f(3)}={f(1)} \cdot {f(2)}=({-2}) \cdot {5}={-10}$ $f(3)=-10$